Multiple piston



July 30, 1929. c. Y. KNIGHT MULTIPLE PISTON Filed oct, 6, 1922 Ili ff lll 1 L llilll 2 M ,M n

vwcwdcoz www @a/LY m @brom Patented July 30, 1929.

UNITED vSTATESV i matas Fries."

CHARLRs Y. KNIGHT, or 1 AsA:oRNA,v CALIFORNIA, AssIGNoR To KNIGHT AMERICAN rATRNTs COMPANY, or CHICAGO, ILLINOIS, A CORPORATION on nELAw'ARR.VV

MULTIPLE PISTON. i

Application med oetober e, 1922. serial No. 592,911.

,This invention relates to a multiple or two-part piston in which the exterior may be made of castiron-to provide for the advantageous use of cast iron in contact with the 5 cylinders in the ,ordinary use in internal combustion engines-and the interior made of a light weight materialsuch as aluminum for example to provide a light weight even section piston construction with the advan- .tages of providing vfor good cooling and rendering it possible to machine vthe skirt and headiof the piston all over with the attend- 'ing advantages flowing therefrom.

It is an Obj ect of the invention to construct l a two-part piston of this character which maybe easily assembled and which when assembled may be rigidly held in assembled position, the invention comprehending broadly the employment of a two-part light weight piston having the different parts constructed of different materials, suchk as those indicated. i Variousy other objects are Within the scope of this invention such as relate to the arrangement of the related elements or the structure, and to various details of construction andV to economies of manufacture and numerous other features as will be apparent from a consideration of the drawing and 3o related description of a form of the invention, which may be preferred, in which- Fig. 1 is a sectional lview of one embodiment of the invention. v l

Fig. 2 is a similar view takenat right angles to thesection of Fig. 1.V "f

y Fig. 3 is a sectional view similar. to Fig. 1 showing a modification .o f the means of securing two parts of the piston together.

Fig. 4 is a similar view of a further mdi' 40 fication. y

Referring to Fig. 1, I have illustrated a castiron exterior inverted shell partl which .may he provided with a plurality of piston ring retaining grooves Q'and'which may be of any desired thickness and may be machined exteriorly on the shirt 1 and the head 3 as heretofore referred to. The lower edge of the skirt 1 is provided withran interior ledge or retaining lip 4, for a purpose. as will presently appear. v y

The interior part yof the twO-partjpiston d is shown as an aluminum casting 8 provided with a. head 9, a body'portion 1() and a plurality of outward extending legs 11. The

under side of the top 3 of the piston exterior portion 1 is provided with a depending cen tral portion or boss 3 and the head 9 of the aluminum interior part 8 is-provided with a corresponding recess 12 which fits over the boss 3f. The head 3 is further 'provided at the central portion of the boss 3 .with a screw-threaded opening 5 to receive a stud or bolt 13 screw-threaded'therein to 'securely re'- tain thevaluminum interior portion Sto the exterior cast iron portion 1 o'f the piston.

To form a secure locking means between the two parts the stud 13 may be screwthreaded to receive the castle nut 1,4 which, -v

as will be apparent, will'securely hold 4the two parts of the piston together at this point of contact,- the locking pin 15 cooperatingwith the castle nut 14 to retain the same in assembled position. The.. aluminum interior yopeningl? to receive the'wr'ist pin 18 for joining the piston to the connecting rod 20.

It will be seen that thefinterior aluminum p casting 8 is therefore provided with a central hollow portion 21- in the body portionvlO thereof in order to receive the endfofl the connecting rod 20 and permit proper operation of the parts in use.`

The aluminum interior casting'S is further retained in position by use ofthelegs 11'having the foot portions 22 which when the parts are assembl'edare adapted to spring over the ledge portion 4 at the bottom of the exterior skirt. It will be seen'fromFig. 2thatthe skirt 1 is provided with openings 2 4 through which the wrist pin 18 is inserted to assemble the piston to the connecting rod and a conventional type of joint between the wrist pin and connecting rod 20 is illustrated at 25.

In Fig. 3 it will beseen that the'head 9 of the interior casting is securedover adepending boss 3 on the bottom' side of the head 3 of thev cast iron shell 1 without need of a'bolt for securing the parts together at this point, Y it being apparent that the legs 11 when sprung inv position place sut'cient pressurev on the parts to securely maintain the two-partpiston fassembled. y n In Fig. 4 a further modification is illustrated in which thehead 9 is'recessed'at9 and provided with screw threadswhile the boss 3 is exteriorly screw threaded 'to receive the same. Otherwise the partsv illustrated in Figs. 3 and 4 correspond to those illustrated skirt, said inner portion being spaced from in l and 2.

It will be apparent that there will be many advantages flowing from t-he construction illustrated as oneembodiment of the invention hereindisclosed. V.A light weight piston is provided which at the same time makes pos# sible the employment of a cast iron sleeve to contact with the cylinder walls in use, an advantage well known in the internal combustion engine art.l At. the same time the parts ma vbe so proportioned as to render an even weightsection of piston throughout which also` has the advantages apparent to those ,Skilled in the art. Y l It is apparent, that, within the spirit of the invention^modi`cations and different arran ements may be made other than as herein disc osed, and the present disclosure is illustrative merely, the invention comprehending all variations' thereof.

I claim: p 1. A two part piston comprising an outer integral part having a head and a skirt yformed'oi" a metal suitable for frictional enagementl with a cylinder, and an inner part orined fof light weight material provided 'with means for connecting a piston rod thereto, said inner part bein protected from direct lcontact with hot com ustion gases by said outer part and contacting withk said outer partfat spaced zones of contact, one of said Zones of contact bei at the. head ofthe piston andthe othery ad]acent the lower edge of the skirt, the lower portion of said inner part adacent said last mentioned zone of contact being resilient, substantially the entire side walls'ofsaid outer part being free from contact with said inner part, and meansrfor securing said parts together.

2. A two part piston comprising an outer part Vhaving a head and a skirt and an inner part provided with means for connecting a piston rod thereto, said inner part' being se- VCured' tothe head' of4 said louter part and spaced from the upper portions of said skirt; means for securing said inner part to the outer part adjacentl to the lower portions of theskirt; and means for automatically secur-- ing saidy inner part'to said outerpart adjacent the lower portion ofthe skirt when said inner Y part is inserted in said outer part.v

` and upper and lower connecting'means. for securing, the inner portion to the head of said outer portion and the lower portion of said same to said head of the exterior portion and a plurality of depending legs to engage said ledge onthe skirt portion and arranged to cooperate with the upper contacting portions of said head and top to maintain the two portions of said piston in assembled position.

` 5. In combination, a multiple part piston having an outer portion with a skirt of a .material suitable for frictional engagement with a cylinder and having a head'and a ledge on the interior ofthe bottom of the skirt and an interior piston rod connecting portion of relatively light weight-material having a wrist pin bearing and a head to ein Yto the head of said skirt'portion, and means to engage saidledge to maintain'said multi-- ple part piston in assembled relation.

6. In combination, amultiple part piston having a skirt portion of a material suitable for rictionalv engagement with a cylinder, having a head anda ledge on the interior of the bottom of the skirt and an vkinterior'pisf ton rod connecting portion having a wrist4 pin ybearing and a head to join the head of said skirt portion, providedfwith inter-engaging screw-threaded means for securing the head of the exterior and head of theinterior portions together.

7. In a piston having avski'rt an interi-or Vpiston part of relatively' light weight material having a top portion adapted to engage the under side of' the top of the piston so as to be protected from directv contact with hot combustion gases, and a central hollow por tion providing oppositely aligned' spaced bearings for the wrist pin of' the piston and rod, the hollow portion ofY said central body part beingarr'anged to receive the connecting rod, said central hollow portion being lspaced from the piston skirt and resiliently contactingtherewith solely at thev bottom edge thereof. i Y

8. An interior piston part Vof relatively light weight material having a topfportion,

a hollow body portion provided with spaced aligned bearingsv for the Wristzpinand; a plurality of retaining legs laring outwardly to enga-ge the lower portionk of the skirt of' the piston, said legs being spaced on opposite sides of the path of movement'of the connecting rod in operation. i

9. A two part piston com rising' anV outer part having a head provide with a central inwardly extendingboss and a skirt, an inner part having a socket receivingsaidbossand secured thereto, said innery part being spaced from the skirt .of said outer part except; at points adjacent the lower edge' thereof at which points said inner part is secured to said outer part.

l0. A two part piston comprising an outer part having a head and a skirt, said head having a central inwardly extending boss, an outer part having a socket receiving said boss and provided with downwardly extending legs, said skirt having an inwardly projecting ledge adjacent its lower edge which is engaged by said legs, and means for securing said inner part to the head of said outer part.

11. A two part piston comprising an outer part having a head and a skirt provided with an inwardly extending ledge adjacent its lower edge, an inner part having a portion engaging the head of said outer part for centralizing the parts with respect to each other, aligned bearings for receiving a wrist pin, and a pair of downwardly extending legs adapted to engage said ledge at dialnetrically opposite points located in a plane at right angles to a plane containing the aXis of said bearing, and means for securing said parts together. 4

In testimony whereof, I ax my signature.

CHARLES Y. KNIGHT. 

